Extensible aerial



AUS- 25, 1953 E. P. GEYER 2,650,302

EXTENSIBLE AERIAL Filed Aug. 26, 1949 gaf 53 ([/37 99 i M2 4., -MeL/q.

Patented Aug. 25, 19513 EXTENSIBLE AERIAL Eugene P. Geyer, Detroit, Mich., assignor, by mesne assignments, to Pioneer Specialty Company, a corporation of Michigan Application August 26, 1949, Serial No. 112,505

(Cl. Z50- 33) 7 Claims.

The present invention relates to telescopically extensible and retractable radio aerials, particularly suitable for use on motor vehicles equipped with radio-transmitting and/or receiving apparatus, although not restricted to such use.

An important object of the invention is to provide improved actuating and controlling means for motivating and for regulating extension and retraction of such telescopic antennae.

An important object of the invention is to provide such a telescopic aerial incorporating a plurality of telescopic sections, all of which are operable by means of a single electric motor, novel and improved means of extreme simplicity and reliability being provided for actuating the antenna sections, as well as novel and improved limit switch controlling means for the electric driving motor.

Other objects and advantages will be apparent upon consideration of the present disclosure in its entirety.

The invention is exempliiied in its preferred form in a unitary assembly which incorporates a telescopic antenna construction and an electric motor having a hollow internally-threaded armature shaft coaxial with but mounted below the telescopic antenna rods, a flexible but substantially inelastic externally threaded rod or Wire extending through the armature shaft and being threadedly interengaged with the internal threads of such shaft. The iiexible wire or rodlike element, which may be termed the driving wire, is preferably formed of insulating material and is connected at one end to the innermost section of the telescopic antenna structure to actuate the same. The limit switch means to control the action of the motor is operable by the driving wire, and the driving wire serves to insulate the contacts of certain of the switching elements from one another when the switch is in the open circuit position.

In the drawings:

Figure 1 is a side elevational view of a telescopic antenna assembly constructed in accordance with the present invention showing the same installed;

Figure 2 is a view upon a larger scale partly in side elevation and partly in substantially central vertical section, with portions broken away;

Figure 3 is a cross-sectional view taken substantially on the line 3-3 of Fig. 2 and looking in the direction of the arrows;

Figure 4 is an elevational vieW of the dual limit switch assembly with one side removed;

Figures 5 and 6 are sectional views of the limit switch assembly taken substantially on the lines 5-5 and 6 6, respectively, of Figure 4 and looking in the direction of the arrows; and,

Figure 7 is a schematic diagram.

Referring now to the drawings, reference character I designates a supporting structure indicated as of sheet metal and which may comprise a body or fender portion of a motor vehicle upon which the aerial is to be installed. The aerial itself may comprise a plurality of telescopic sections, the construction and arrangement of which may correspond to the disclosure of Patent No. 2,580,889 granted January 1, 1952, to Emil Carlson, although the details of construction of the aerial itself are subject to variation, and need not be considered herein, The central or innermost section of the antenna comprises a rod I2, successively enclosed in a plurality of slidable tubular telescopic sections I4, I5 and a fixed outer tubular section I6. It will be understood that the relative travel of each movable section with respect to its next adjacent section is limited so that as each section reaches the end or" its relative travel it can thereafter move only in conjunction with such adjacent section.

The outermost antenna section I6 is xedly supported by, but insulated from, a sheet metal supporting neck member I8 which is of generally stepped cylindrical form, having its upper portion 29, which is of smallest diameter, so formed that it is adapted to project upwardly through an aperture I9 in the body portion I0. The neck is threaded at its upper extermity as indicated at 2| to receive a suitable holding device such as the domed nut 22, which with suitable spacing and gasketing collars as 24, 25, 26, coact to support the antenna structure and housing in generally vertical position and to seal the hole I9, the several antenna sections being thus mounted to project above the body portion It in the manner shown and which is now familiar in the art.

The enlarged lower portion of the neckpiece I8 supports a lead-in terminal element 28 to which a transmission line (not shown) may be connected to connect the antenna structure to the radio apparatus. The lower end of neckpiece I8 is open and suitably outwardly anged and secured as by the screws 30 to the upper end of the housing of the vertically disposed electric motor assembly 32. The electric motor may be of a conventional construction and will require no detailed description. It is of the reversible type and, of course, adapted to operate upon the current supply available from the vehicle battery, under ordinary conditions.

The armature shaft 33 of the motor is o hollow tubular form and internally threaded, at least at one end, as indicated at 3ft, the shaft being open at both ends of the motor and coaxial with the antenna rod assembly. A belled sheet metal closure 35 is secured to the lower end of the motor as by the saine screws 3g), which may be `the screws employed to secure together the stator structure and the casing portions of the motor. The bell 35 has a downwardly projecting, externally threaded central boss 35 which is provided with an axial aperture 3S slightly larger than the threaded portion of the central hole in the armature shaft.

A flexible but substantially inelastic rod or wire 4G formed of a suitable plastic having highinsulating characteristics, and also relatively great tensile strength, is secured to the central antenna section I2 and extends downwardly through the hollow armature shaft and the hole 38 in -boss 35. The driving Wire il@ may be formed of nylon and is provided with continuous external screw threads which are threadedly interengaged with the internal threads Sil of the armature shaft,

Secured to and extending downwardly from the nipple portion 3 6 is a sheathing tube d2 in which the wire 40 is freely slidable. The lsheathing tube ft2 may be formed of metal `and is sufficiently stiff to resist distortion fby the actuating wire, Directly below the electric ino-tor casi'ng 552 the sheathing tube is looped once upon itself. Such looped portion is designated lit and in the form of a 'smooth curve which is great enough in radius so that the actuating wire is easily slidable therethrough. Such looped portion effectively prevents the actuating wire frein twisting about its own axis in response to rotation of the motor armature, so that when the armature is rotated, the actuating wire is forced to move upwardly and downwardly through the armature shaft 33 to project and rotratt the telosoopio sections of the antenna assembly.

Tho Slooathing tubo may be bent t0 any of a variety of shapes to facilitate its installation and is in fact suiciently easily bendable so that it may be shaped during installation of the antenna assembly, to adapt the assembly for in- Stallation upon vthiolos` having different body contours. The loop dii is close enough to the motor, and the driving wire 4E] is long enough, so that the driving wire is never pulled out of the loop 44 even when the antenna sections are fully projected.

Frein thelooped portion dit, the sheathing tube is shown as extending horizontally a short distance to a dual limit switch casing, generally designated d5. Details of construction of the dual limit switch assembly are best shown in Figs. 4, 5. and 6. is there indicated, the casing structure is formed of two relatively flat complemental sections 4t, 131, which may be of molded plastic and which are contoured to provide two parallel longitudinal passages therethrough, suh passages being deined by mating channels formed one-half in each of the casing sections 45, 4l. yOne such longitudinal passageway defines an elongated chamber which is generally designated 5B and which serves to house a limit switch generally designated 52. Switch 52 limits the extent of upward or projecting movement of the antenna sections. The other 4parallel passageway defines an elongated chamber generally designated 55 which houses d another limit switch structure generally designated 51. Switch 51 limits the extent of downward or retracting travel of the antenna sections.

The sheathing tube structure is interrupted in the area of each switch chamber so that in the region of each of the limit switches the driving wire is exposed within the casing structure. The two longitudinal passageways are spaced from one another far enough to provide clearance for a pair of securing screws or rivets as 58 which hold the two casing sections together, and also to provide clearance for a central hole as BQ which extends through both casing sect-ions and which is adapted to permit the projection therethrough of a supporting screw (not shown) to enable the switch structure to be secured to a wall or frame portion of a vehicle. At each end, each of the chambers 5G, 55 is provided with an open-ended substantially cylindrical terminal portion as S4, 64', 562, 5,43, of such size as to lit snugly over and retain the `end of the sheathing tube. Each such cylindrical tube-engaging portion is dared at its inner end, as indicated at t5, 6,5', `(52, 553, to receive a conventional flare formed upon the retained end of the sheathing tube. The sheathing tube sections are thereby positively positioned and held against separation when the switch casing sections are secured together.

Within the chamber 5I.) of the switch casing is a switch blade S6 formed of spring material such as phosphor bronze. -One end of the blade Sli is secured to casing section 4S by a terminal post 6o. The other free end of the blade is movable to and from engagement with a contact 10 formed upon the inner end of a terminal post l2 and located Within, the Chamber 59. The frto ond of the blade `it is biased to move away from the contact l but can only do so when the driving wire lil is pulled out of the chamber portion 50, When. the driving wire is in the Chamber, it pushes the. blade S5 into engagement with Contact lt to provide an electrical connection between posts Sii., l2 in the manner Shown in Fig. 6.

Within the chamber 55 in the switch casing.`

are a pair of resilient conductive switch blades.

lia, l5, which are supported, respectively, by terminal posts l5, 78 carried by the switch cas.- ins Sections d'6., lll. The posts lt, lo are in 'transverse aXial alisnmentwith one another near one end of the chamber 55, and the blades 14 l5 project. longitudinally in. the same direction from the posts and are` biased tc move into oontact with one another, although they are held apart when the driving wire is projected between them. As best shown in Fig, 4, the blades lill, 'lli are substantially wider than the diameter of the wire at their outer ends. The widened portion of the blade 'M dcigated l, and, at cath edge ofV auch. widened. portion, an integral tongue 8,8, 8l, is bent angularly inwardly toward the correspondingly widened end portion 82 of the blade l5. Thus when, the driving wire is pulled from between the yblades ifi, l5, such blades move toward one another untilthe tongues, 85, 8lv engage the end' portion 82; of the blade l5, Electrical contact between the blades is thus made by portions which` are not engaged by the driving wire, and it will. be observed that the portions whichcare thus relied upon to make the electricalV contact are relatively sharp,` so Ythat4 if any dirt is carried into engagement withn the Iblades by the 'driving wire, it cannot interfere with proper electrical contact between the tongues 80, 8l and the switch blade portion 32.

After leaving the region of the loop 44, the

sheathing tube is connected to the holding por-- tion 64 at the left end of the chamber 50, as the parts are viewed in Figs. 4 and 6. The continuation portion 42 of the sheathing tube which eX- tends from the right end of chamber 59, as shown in the view ljust referred to, is held by correspending casing portions 64', 65. Such portion of the sheathing tube is formed in a smoothly curved loop of substantial diameter, as best shown in Fig. 1, and is returned to connection with the right end of chamber 55, where it is secured by similar holding portions 642, 652, at the right end of the switch casing, as the parts are viewed in Figs. 4 and 5. It will be appreciated that the driving wire only projects between the switch blades 14, 'i5 when the antenna is fully retracted and that the driving wire thus need only be long enough to project between the blade portions '59, 82, although to afford a margin of safety the driving wire is shown as long enough to project an inch or two beyond the blades 14, T5, such projecting portion being housed in a short extension section 422 of the sheathing tube which is secured with respect to the switch casing by means of similar positioning and iiared portions 543, E53. The terminal housing section 422 of the sheathing tube is flattened or otherwise closed at its free end, as indicated at 84.

The dual limit switch assembly is located relatively close to the looped portion 44 of the sheathing tube and the parts are so proportioned that the driving wire is only pulled from engagement with the switch blade 96 when the aerial is fully projected.

A suitable electric circuit is indicated in Fig. 7, in which view the source of electrical energy is indicated as a battery 99, which may comprise the storage battery of the car. One terminal of the battery is grounded as indicated at 92. The other battery terminal is connected by a wire 93 to the blade 94 of a single pole-double throw switch, one terminal 95 of which is connected by means of a wire 96 to the switch contact 10 previously described. The other contact point 91 of the single pole-double throw switch is connected by means of a wire 98 with one of the switch blades 74, previously described. The other switch blade i5 is connected by means of a wire 99 to one contact of the reversible electric motor 32. Another terminal of the motor is connected by a wire i 00 to the switch blade 66, while the other terminal of the moter is grounded by the wire 92.

When the switch blade 94 is moved into engagement with the contact 95, considering that the aerial is initially in its retracted position, the motor is rotated in a direction to project the aerial, and throughout such projection the switch blade 6B is held in engagement with the contact point iii by the driving wire 4U, and such engagement is maintained unless or until the antenna is fully projected to move the wire 40 to its extreme position in which it is clear of the switch blade 66 and the blade is allowed to open, as previously described. As soon as projection of the aerial commences, the switch contact portions of the switch blades 14, engage one another to complete a connection between switch terminal 97 and the motor 32, so that at any time, the direction of rotation of the motor may be reversed by moving blade 94 to engage switch contact 91. This will cause energization of the motor in a reverse direction 'to retract the antenna, and such retracting movement continues, if the switch is held closed, until when the aerial is fully retracted the wire 40 moves between and separates the switch blades 14, 15, which again stops the motor.

While it will be apparent that the preferred embodiment of the invention herein disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modication, variation and change without departing from the proper scope or fair meaning of Athe subjoined claims.

What is claimed is:

1. In an extensible and retractable telescopic aerial construction of the type which incorporates a movable aerial rod, an electrically controllable motor, an elongated flexible but substantially inelastic driving element formed of insulating material drivable by the motor and connected to the rod to drive the latter in response to energization of the motor, a sheathing tube in which said element slides when so driven,

at least a part of said sheathing tube being looped back upon itself so that two longitudinally spaced portions of said sheathing tube through which the element slides lie relatively close to one another in a lateral direction, parts of the sheathing tube being interrupted in two areas located at said close portions, and a dual limit switch structure for controlling the energization ci the motor including two switching devices, one such switching device projecting into each interrupted part of the sheathing tube.

2. Means as defined in claim 1 wherein said dual limit switch structure comprises a housing having a pair of passages therein through which said element is adapted to slide, and contact members carried by the housing and extending into the passages for engagement with said element.

3. Means as defined in claim 1 wherein said dual limit switch structure comprises a housing 'i Iormed of a pair of complemented-casing sections having channels therein dening switch housings through which said element is slidable, and retaining portions for said sheathing tube, said retaining portions comprising recessed extensions of said channels interengageable with said tube.

li. Means as defined in claim 1 wherein said limit switch structure comprises a casing engageable with and adapted to serve as a support for such longitudinally spaced portions of the sheathing tube.

5. Means as dei-ined in claim 1 wherein one switching device comprises a pair of contacts 1ocated on one side :of the driving element and adapted to be maintained in electrically conductive engagement by said element and a second pair or contacts one contact of which is located on each side of said element, said second pair of contacts being adapted to be maintained disengaged by said element, and means biasing the contacts of the rst-mentioned pair apart and the contacts of the second-mentioned pair to' gether.

6. Means as dened in claim 1 wherein one switching device located closer to the motor comprises a pair of contacts located on one side of the driving element and adapted to be maintained in electrically conductive engagement by said element and a second pair of contacts one contact of which is located on each side of said element, said second pair of contacts being more remote from the motor, measured along the sheathing tube and adapted to be maintained disengaged by said element, and means biasing the contacts o1 the first-mentioned pair apart and the contacts of the second-mentioned pair together.

7. In an eXtensible and retractable telescopic aerial construction of the type which incorporates a movable aerial rod, an electrically controllable motor, an elongated Iiexible but substantially inelastic driving element formed of insulating material drivable by the motor and connected to the rod to drive the latter in response to energization of the motor, a sheathing tube in which said element slides when so driven, and a limit switch structure comprising two pairs of contacts, the contacts of one pair incorporating one contact yieldably biased to tend to move into engagement with the other, said element being 20 movable to and from an interposed position with 8 respect to said contacts when the aerial is near' the fully retracted position, whereby the element may in one positionseparate and insulatev said contacts from one another and in another position permit said contacts to move into electrically conductive engagement with one another, the contacts of the other pair incorporating one contact yieldably biased to move out of engage'- ment with the other, said element being movable to and from a position wherein it urges the contacts of said last mentioned pair together when the aerial is near the fully projected position.

EUGENE P. GEYER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,299,785 Barrett Oct. 27, 1942 2,329,329 Brach et al Sept. 14, 1943 2,368,298 Harris i-. Jan. 30, 1945 

